The present invention relates in general to trunk performance monitoring in a telecommunications network, and, more specifically, to a tool for assisting network monitoring personnel to rapidly detect trunk failures in a manner that highlights the failures which have the greatest affect on network performance.
Telecommunications systems such as the public switched telephone network and cellular wireless networks include switches for forwarding traffic to the appropriate destinations. The communication channels for carrying traffic between switches are known as trunks. Trunks may interconnect switches to other switches or to other traffic nodes such as a base station controller in a wireless cellular system.
Trunks are also sometimes referred to as circuits. As used herein, trunk refers to any single transmission channel between two points. A trunk group is two or more trunks that connect the same two points (e.g., switches or nodes) and are connected in such a way that if a call is routed to the trunk group and a free circuit is available in the trunk group, then the call will be routed on the free circuit. The trunk groups included in a network are laid out between the switches and nodes in a quantity that provides the capacity needed to optimally handle traffic loads experienced within the network. When trunks fail for any reason (e.g., such as the result of a hardware fault) the overall traffic carrying capacity is reduced and may result in blocked calls. A control center is provided within the telecommunications network for monitoring trunk failures so that traffic can be rerouted as necessary and steps can be taken to repair the failures.
Each trunk circuit is typically implemented as part of a DS-1 span which is a plurality of circuits that are multiplexed together into one digital signal for transport between switches. Each DS-1 span includes 24 circuits. A failure may affect a single circuit or an entire DS-1 span. During operation, a switch keeps track of the aggregate total time that circuits are out of service over given periods (e.g. each half hour).
Trunk failures have typically been monitored by control center technicians by inspecting log messages and/or alarm messages that are transmitted by the switches to the control center. However, this has required technicians to sort through massive amounts of other log and alarm messages. Consequently, the response time to detect and address trunk failures is slow and such failures are often not even noticed at the time the first log or alarm messages appear. Therefore, it would desirable to reduce the burden on technicians for monitoring trunk health and to speed up the detection of trunk failures.